#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int arr[10] = { 0 };
	double sum = 0;
	int i = 0;
	for (i = 1;i <= 10;i++)
	{
		scanf("%d",&arr[i-1]);
		sum = sum + arr[i - 1];
	}
	printf("%f",sum/10);
	return 0;
}
